truncated_square_root.cpp: Used binary search

Used binary search for root. Used bit manipulation instead of
division.

Author: mouri11

Math/truncated_square_root/a.out

@@ -4,14 +4,28 @@
 
 using namespace std;
 
+typedef long long int lli;
+
+lli flrSqrt(lli n) { // using binary search to calculate square root
+    if (n == 0 || n == 1) return n;
+    lli start = 0, end = n/2, ans;
+    while (start <= end) {
+        lli mid = (start + end) >> 1;
+        if (mid*mid == n) return mid;
+        else if (mid*mid < n) {
+            start = mid + 1;
+            ans = mid;
+        }
+        else end = mid - 1;
+    }
+    return ans;
+}
+
 int main() {
-    long long int n,x = 0,count=0;
+    lli n;
     cout<<"Enter an integer: "<<endl;
     cin>>n;
-    for(int i = 1;x <= n;i += 2) {
-        x += i;
-        count++;
-    }
-    printf("Square root of %lld is: %lld\n",n,count-1);
+    if (n < 0) return 0;
+    printf("Square root of %lld is: %lld\n",n,flrSqrt(n));
     return 0;
 }